From: Baolu Lu <baolu.lu@linux.intel.com>
To: Jason Gunthorpe <jgg@nvidia.com>,
David Woodhouse <dwmw2@infradead.org>,
iommu@lists.linux.dev, Joerg Roedel <joro@8bytes.org>,
Robin Murphy <robin.murphy@arm.com>,
Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>,
Will Deacon <will@kernel.org>
Cc: Calvin Owens <calvin@wbinvd.org>,
Chaitanya Kumar Borah <chaitanya.kumar.borah@intel.com>,
Joerg Roedel <joerg.roedel@amd.com>,
Kevin Tian <kevin.tian@intel.com>,
patches@lists.linux.dev, Tina Zhang <tina.zhang@intel.com>
Subject: Re: [PATCH 1/2] iommupt/vtd: Allow VT-d to have a larger table top than the vasz requires
Date: Fri, 28 Nov 2025 14:54:04 +0800 [thread overview]
Message-ID: <c583ed29-34a0-4ab2-bd2c-2fa94ea1a647@linux.intel.com> (raw)
In-Reply-To: <1-v1-ae5d7f0f2620+13b-vtd_mgaw_jgg@nvidia.com>
On 11/28/25 07:54, Jason Gunthorpe wrote:
> VT-d second stage HW specifies both the maximum IOVA and the supported
> table walk starting points. Weirdly there is HW that only supports a 4
> level walk but has a maximum IOVA that only needs 3.
>
> The current code miscalculates this and creates a wrongly sized page table
> which ultimately fails the compatability check for number of levels.
s/compatability/compatibility/
>
> This is fixed by allowing the page table to be created with both a vasz
> and top_level input. The vasz will set the aperture for the domain while
> the top_level will set the page table geometry.
>
> Add top_level to vtdss and correct the logic in VT-d to generate the right
> top_level and vasz from mgaw and sagaw.
>
> Fixes: d373449d8e97 ("iommu/vt-d: Use the generic iommu page table")
> Reported-by: Calvin Owens<calvin@wbinvd.org>
> Closes:https://lore.kernel.org/
> r/8f257d2651eb8a4358fcbd47b0145002e5f1d638.1764237717.git.calvin@wbinvd.org
> Signed-off-by: Jason Gunthorpe<jgg@nvidia.com>
Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com>
next prev parent reply other threads:[~2025-11-28 6:58 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-11-27 23:54 [PATCH 0/2] Fix VT-d when the IOVA limit is small Jason Gunthorpe
2025-11-27 23:54 ` [PATCH 1/2] iommupt/vtd: Allow VT-d to have a larger table top than the vasz requires Jason Gunthorpe
2025-11-28 6:54 ` Baolu Lu [this message]
2025-11-27 23:54 ` [PATCH 2/2] iommupt/vtd: Support mgaw's less than a 4 level walk for first stage Jason Gunthorpe
2025-11-28 7:03 ` Baolu Lu
2025-11-28 0:04 ` [PATCH 0/2] Fix VT-d when the IOVA limit is small Jason Gunthorpe
2025-11-28 7:48 ` Joerg Roedel
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